1. Field of the Invention
The present invention relates broadly to magnetic tape drives and cleaners and more specifically to a method and apparatus for cleaning, re-tensioning, scanning, evaluating, recording, and reading magnetic tape cartridges.
2. Description of the Prior Art
Magnetic tape has long been the standard in data storage and retrieval. Today magnetic tapes have greater areal density (information storage capability per unit of tape area) than ever before. For example, the areal densities achieved with the IBM 3480 (trademark) half-inch cartridges are six times greater than those achieved with older half-inch open reel tapes. Even these areal densities are expected to further increase by a factor of at least 20 during the next decade. These increased densities have created a situation in which tapes and related reading and recording devices must be far more sensitive than ever before. Therefore, tape damage and airborne contamination that accumulates on tapes, which in the past would have gone unnoticed by reading and recording devices, now often results in loss of data, reduced reliability, and even down time due to equipment failure. Accordingly, these increased tape densities have created a greater need for an effective tape maintenance program. For example, when airborne contamination deposits and builds up on the inside surface of a tape to the point that it causes a mere 10-microinch separation between the tape and a reading device head, some problems in data retrieval can result. such airborne contamination builds up to the point that it causes only a 20-microinch separation between the tape and a reading head it can be devastating to data retrieval. To put this sensitivity in perspective, a smoke layer on a magnetic tape typically causes a 200-microinch separation between tape and head.
Accordingly, there is an increased interest in devices for cleaning magnetic tapes. Similarly, there is interest in devices for scanning tapes to detect physical defects, such as edge damage or stretched tape, which can also interfere with data recording and retrieval. Current systems designed to address the cleaning needs typically include a burnishing blade and multiple tissue wiping stations for dislodging and removing contamination. While such devices provide some beneficial cleaning, they tend to be large, bulky machines with long, undulating, and tortuous tape paths. These long tape paths are often used to facilitate numerous cleaning stations as well as to dampen motor drive oscillations. However, they have also resulted in nonuniform tape tension profiles, which can render tapes more susceptible to damage, accumulation of contamination, and difficulty in data retrieval and recording, as well as reduced system productivity.